The longevity of Drosophila mutants at the per locus and wild-type controls will be measured in a variety of periodic and aperiodic environmental conditions. Longevity of populations of 100 flies per bottle will be measured, as well as locomotor activity and longevity of individual flies. Correlations between lifespan and amount of activity per cycle, amplitude of the activity rhythm, and desynchronization of the activity rhythm will be analyzed. The relationship between genetically determined periodicity and longevity in the various environments will be studied.